Hydraulic gear



. `7, 1930. w. KUHN HYDRAULIC EvAR med April 14. 1927 2 Sheets-Sheet 1 Oct.` 7, 1930. l l w. KUHN v 1,777,351"

'HYDRAULIC GEA? Filed April 14.' 1927 2 sheets-Shen 2 Patented oet. 7, leso UNITED c STATES PATENT ori-lcs WILHELM KHN, or rnANxron'r-ON-rHE-nanv-nscnnnsnm, GERMANY HYDRAULIC GEAR- Application med April 14, 1927, Serial No. 183,751., and in Germany Kay 25, 1926.

in each unit. It is an object of my invention t'o improve a gear of this type with a view to increasing its range of applicability. To this end I provide a connecting element between the two units by which the displacement of one unit is transferred onto the other unit, but in whichseparate adjustment ofthe other unit independently of the rst unit is gramma'tically byway of example.

also possible.

By these means the applicability of hydrauli'c gears isincreased to-such,` an extent,

2,0 that they are nowapplicable under operating- 'conditions and for purposes for which they were not suitable heretofore.

In a preferred embodiment of my invention I provide means for displacing the cyll inder of the motor unit. 1 The connecting element is constructed as a rod connecting the two units 'andadapted to transmit the motion of the motor unit to the' pump unit, but not vice versa. Preferably the range ofec- '30 centricity ofJ the vmotor unit exceeds that of the pump unit so that a comparatively small Vdisplacement of the4 motor unit effects a considerable variation in the eccentricity of the pump unit. v The connecting element permits independi ent adjustment of one of the units, in the present instance of the pump unit, so that the eccentricity of the pump unit may be varied even after the motor unit has reached 4 its limit of adjustabinty.. similarly, a is l also possibleto so adjust theconnecting element that it will become operative only after the unit by which the connection is operated,

i hasbeen displaced through a given distance.

Another advantage of the connecting element is that it permits the pump unit to be rendered inactive by reducing. its eccentricity to zero, that is, placing the axes of the rotor and the cylinder in concentric position, in-

e rotor. In such gears it has been dependently ofthe position which the motor unit assumes at the time. y I `may also reverse the direction in which the motor unit rotates, by dis lacing the pum unit so as to reverse the irection in 4whic it delivers liquid to the motor unit.

In the followingspecication I shall describe in the iirst place change speed gears in which the motor unit is displaced and entrains the pump unit, but it is understood that this arrangement may be reversed without departing from my invention, as will be described further on.

In the drawings atlixed to this specification l and forming part thereof change speed gears embodying my invention areillustrated dia- In the drawings vertical gear. Fig. 1a isa section on the line 1- in Fig. 1,v drawn toa larger scale,`

Figs. 2 and 3 are diagrams illustrating V the .reversing of the motor by displacing the pump cylinder,

Figs. Land 6 illustrate,` somewhat diagra;nmatical1y,the arrangement ofthe gear in connection with the frame of a machine tool, and Y Fig. 5'is a transverse'section of a horizon-l tal non-reversible gear. l

Referring now to the drawings, and first to Fig. 1, 1li is the casing of the gear in which the cylinder 1 of the pump unit and the cylinder 2 of the motor unit are adapted4 to be displaced. The units are equipped'l with the usual-shafts 21 and 22, rotors v23 and 24,v and vanes 25 and 26, respectively.

.Rotation is imparted to the shaft 21 of the of the motor cylinder 2 with the position of thecylinder in which the eecentricity of the motor unit is a maximum. In this position a shoulder 32 ot the boss 3l abuts against a corresponding shoulder in the casing. The limit in the opposite direction is constituted by a shoulder 33 at the lower end of the cylinder which in the lower inal position of the cylinder 2, correspond- .I ably supported in a parallel guide in the base of the casing 14 and its stroke is limited by abutments 7 and 3G at the lower and upper ends of the guide.

4 is a rod which is inserted in a threaded hole in the top of the pump cylinder 1, 37 is a flange or dog at the upper end of the rod 4, and 5 is a shouldered sleeve or abutment screwed into a threaded hole in the base of the motor cylinder 2. The range of the connecting element, that is, the distance through which the cylinders 1 and 2 may be displaced with respect to each other, is determined by the clearance between the flange 37 and the corresponding face at the base of the motor cylinder. A spring 6 which 1s inserted between the top of the pump cylinder 1 and a transverse bar 38 of the casing 14 tends lto hold thelange 3T engaged with the shoulder of the sleeve 5'. Consequently, the relative distance of the c ,l'lindelrs 1 and 2 in the direction in which the connecting element operates, is determined by the length of the rod 4, and the effective length of the rod may be varied by turningthe rod in its threaded hole at the top of the pump cylinder 1. Rotation of the rod 4 may be effected by any suitable means. In the present instance the transverse bar 38 is divided and va Worm gear 39 is inserted therein andV connected with the rod 4 by a spline 40 and a key 41. Rotation is imparted to the wormgear 39 by means of a worm 42 on a shaft 43 in the casing 14 which is rotated by a hand Wheel 8. In this manner the rod 4 may be screwed out of, or into. its hole in the cylind er 1 as desired, and its effective length varie Means may be provided for rendering the pump lnoperative at any time and independently of the adjustment of the motor cylinder 2. In the present instance, this is effected by a handle 9 on a shaft.- 44 and a cam 10, also on the shaft 44, which engages a collar l1 on the rod 4.

The pump illustrated in Fig. 1 is adapted to rotate in either direction and therefore is provided with safety valves 12 and 12 and make-up valves 13, 13 on both sides. rl`he safety valve 12 is shown in section in Fig. l. .121 is a valve casing which is inserted in the bottom of the pump cylinder, 122 is the spindle of the valve, and 123 is the, spring which tends to hold the valve on its seat. The make-up valve 13 has been shown in Fig. 1". It comprises a bush which is threaded into the wall of the pump cylinder and perforated at 131, and a valve body 132 on a seat 133.

The valves 12, 12 are normal safety valves which are adjusted for a given pressure by varying the tension of their springs. Then the predetern'iined pressure is exceeded, for instance, wheuthe load on the motor unit beA comes excessive or when an unusual resistance occurs in the gear on account of irregularities, the valves will open and permit liquidpto escape into the oil chamber surrounding the pump cylinder until normal pressure has been reestablished. Loss of liquid due to the operation of the safety valves or to leakage is made up for by the valves 13, 13 which open when the pressure in the liquid chamber exceeds the pressure 011 the suction side of the pump. As will appear from Figs. 2 and 3, the pump cylinder 1 may be so displaced with respect to its rotor 23 that the direction in which the rotor 24 in the motor cylinder 2 is rotating, is reversed. The distance D between the centres of the shafts 21 and 22 is constant but the eecentricities E and c ot the pump and motor cylinders. respectively, are variable. ln Fig. 2 the motor cylinder 2 is adjusted 'for any desired ecccntricity c which may be varied as described, but thepump cylinder l has been adjusted to its limit of eccentrieity so that its rotor 23 is in contact with the cylinder 1 at its upper side. The rotor 23 rotates clockwise, the liquid flows down in the pipe 3 and up in the pipe 3 and rotation is imparted to the rotor 24 of the motor in clockwise direction. When, however, the position of the pump cylinder 1 is reversed with re spect to its rotor, as shown in Fig. 3, so that the lower side of the rotor is in Contact with the pump cylinder, the-flow in the pipes 3 and 3 will be short-circuited, that is, the liquid will flow from the pipe 3 to the pipe 3 at the' side of the pump cylinder which is facing the motor cylinder Without flowing about the rotor 23 of the pump, as shown in Fig. 2. The, consequence is that the liquid flows down in the pipe 3 and up in the pipe 3 and so anticlockwise rotation is imparted to the rotor 24 while vthe rotor 23 still rotates clockwise. i It will be understood that the motor, notwithstanding the reversing of the direction in which its rotor 24 is rotating, may be adjusted Within the range of its eccentricity, as described above.

, Referring now to Fig. 4, 45 is an uprightV of a machine tool, for instance, a lathe or the like and 46 is a bracket on the upright in which lthe casing 14 is pivotally carried. A sprocket 47 is secured on the shaft 22 at the rear of the casing and a chain 48 imparts rotationto a sprocket 49 on a shaft of the machine. A pinion 50 is keyed on the latter shaft and meshes with a wheel51 on a parallel shaft. V t

In thiscase the handle 9 for throwin out the pump unit is arranged yon a sha t 52v which is carried in the base of the casing 14 and a cam on the shaft 52 corresponding tothe cam 10 on the shaft 44 in Fig. 1 acts directly on the cylinder 1 instead of acting on the collar l1. This modification has not been illustrated as it will be understood by any expert.

. Instead of being pivotally carried Aon the upright, the casin 14 maybe secured to the upright by a suita le face plate, as'isshown in Fig. 6.

Referring now to Fig.i5 this gear is de- .signed on the same principle as that illus-l trated in Fig. 1, and corresponding parts have been indicated bythe same reference numerals and will not again' be described.

\ The pump of this gear is not reversible and therefore its pum cylinder 1 is provided `only with a single sa ety valve-12. The rod 4 is replaced by a tube 53 in which a spring 54 corresponding to the spring 6 in Fig. 1 is inserted. It will be understood that the operation ofthe connecting element between the cylinders 1 and'2 is the same as that described with reference to Fig. 1 and that the means forvarying. the effective length of the rod which have been described with reference to Fig. 1, maybe applied although they havev not been illustrated. On the other hand, in

this case it is not necessary to throw out the pump by means of thel handle 9 when it is desired to arrest the motor as the pump rotates in one direction only, and therefore in this case it suiiices to provide a -by-pass or relief valve generally indicated at -17 by which the liquid under pressure from the delivery pipe 3 may be by-passed into the casing from the cylinder 1. This valve'comprises a valve body 170 which is seated on a.

tapered: face in the body 'of the cylinder 1, and is provided with a spindle 171 for operating it.

In the present instance means are provided in connection with the cylinder `1 of the pump for equalizing transverse forces so as to facilitate its movement in the guide 35.- Grooves 15 and 15 are formed in the outer face of the cylinder 1 and connected .with the space within the cylinder by bores 16 and 16. Obvious- .y ly, the grooves and bores might also be provided on the cylinder 2 ofthe motor, particumachine which 'per .erted at the wheel 30 and the spindle 19 is so considerable that equalizing means are not indispensible in the motor cylinder. The size ofthe cylinder is only a secondary consideration with respect to the equalizing system, the

primary consideration being the general type of supports for the cylinder. The equalizing system is provided whenever the area available for guiding the motor cylinder 2 is comparatively large.

The splgot at the end of the motor cylinder tits the guide 35 in which the pump cylinder 1 slides. At the opposite end of the motor cylinder is provided with the boss 31 and the parts connected therewith, including the hand wheel 30, are the same as described with reference to Fig. 1. Y.

Referring now to Fig. 6, thisillustrates the adaptation of my gear to the frame55 of a ments, for instance, a'planer. 63is a :Bange at one side of the casing .14, by which it is orms reciprocating movesecured '.to the frame 55, and 27 'is a pulley 'i which is secured on the pump shaft 21.

The pump is adjusted and reversed as described with reference to Figs. 2 and 3. Any

suitable means may be provided for connecting the gear 14 with moving parts of the machine so as to control its operation in conformity with the operation of the machine.l For instance, Imay provide a pinion, not shown, on the shaft 22 of the motor which meshes with a rack on any reciprocating part of the machine, for instance, its table, not shown. Lugs 64,- 64 are carried on, or operatively connected with, the reciprocating part andare fitted to slide on a bar 56. Fitted tO- slide on the bar between the lugs is a sleeve 65 with a pin 59. 57 is a double-armed leverv which is fulcrumed on the frame 55 at 58 and engages the pin with a slotted eye at the end of its upper arrn,'and 60 is a link connected with an arm 61 on a shaft 18'for regulating' the position of the pump cylinder 1. The shaft 18 corresponds to the spindle 19 in Figs. 1 and 5 but in the resent instance the shaft 18is equipped wit that the cylinder is reciprocated upon rotation of the shaft. This mechanism controls the motion required for adjusting the gear by displacing thepump cylinder and the motor cylinder merely moves in conformity with the motion of the pump cylinder, being connected a cam or the like, .notf Y shown, for engaging a recess 1n, or a pro]ecf tion` on, the pump cylinder 1, 1n such manner v the motor is rotating at its Obviously the ratio may is ad]usted. The check 62 has been indicated in Fig. 3. The displacement of the pump causes a corresponding displacement of the motor, the means ior edecting this being the same as when, conversely, the pump is displaced by the motor. Fig. 3 shows the motor cylinder in its upper final position and engaged with the check 62. In this position normal speed corresponding to the operating or forward stroke of the bar 56. The eccentricity of the motor cylinder 2 and its rotor 24 is comparatively large as shown in Fig. 2 and Jfor the sake of simplicity the pump is shown at maximum eccentricity. When the pump cylinder 1 is now moved downwardly from the position illustrated in Fig. 3 by the system 57, 60, 61 it will entrain the motor cylinder 2 through a certain small distance and move it out of contact with the check 62. By displacing the pump cylinder the motor is reversed but at the same time its eccentricity is reduced while theeccentricity of the pump cylinder is the same but opposite its original eccentricity, as shown in Fig. 2. The output of the pump therefore is not varied but the speed of the motor is increased and the return stroke of the bar 56 is performed at this increasing speed. When the pump is again reversed, the several operations will occur in, opposite sequence. The motor cylinder is entrained by the pump cylinder until it is arrested by the check 62 while the pump cylinder moves into its position of maximum eccentricity in upward direction and independently of the motor cylinder as shown in Fig. 3 and the gear is now rcady' for another forward stroke of the bar 5 For a given position of the check 62 and with a given displacement of the pump cylinder from its upper position in Fig. 3 into its lower posit-ion in Fig. 2 the ratio of the forward and return speeds of the motor and consequently of the bar 56 will be constant, the return stroke being performed at a higher speed than the operatin or forward stroke. varied by varying the displacement of the pump cylinder or the position of the check 62, or both factors. For a given adjustment, however, the operating conditions will be the same.

In the present instance, the casing 14, instead of bein fulcrumed to the upright 55, is connected t creto by means of a face plate the art.

I claim 1. A hydraulic change-speed gear comprising a motor unit and a pump-unit, each unit having a casing and a rotor, means for varying the relative position of said casing and said rotor of each unit, and a connecting element between those parts o'the units which Vare displaced for varying said relative position, said element being fixed to one of said parts and adapted to move within limits with respect to the other part.

2. A hydraulic change-speed gear comprising a motor unit and a pump unit, each unit having a casing and a rotor, means for varying the relative position of said casing vand sald rotor of each unit, and a connecting element between those parts of the units which are displaced for varying said relative position, said element being iixed to one of said parts and adapted to move within limits with respect to the other part, said motor unit having a larger range within which said relative position can be varied than said pump unit.

3. A hydraulic change-speed gear comprising a motor unit and a pump unit, each unit having a casing and a rotor, means for varying the relativey position of said casing' and said rotor of each unit, a connecting element between those parts of the units which are displaced for varying said relative position, said element being fixed to one of said parts and adapted to move within limits with respect to Vthe other part, and means 'for varying the effective range of said connecting element.

4. A hydraulic change-speed gear comprising a motor unit and a pump unit, each unit having a casing and a rotor, means for varyin the relative position of said casing and said rotor of each unit, a connecting element between those parts of the units which are displaced for varying said relative position, said element being fixed to one of said parts and adapted to move within limits with respect to the other part, and means connected with said element for displacing that part to which said element isfixed, independently of the other part. i

5. A hydraulic change-speed gear comprising a frame, in said frame, each unit having a casing and a rotor, each casing having a cylindrical part, guides for the parallel displacement of each casing in said frame, and a connectin element between said casings, said element eing fixed to one of said casings and adapted to move within limits withrespect to the other 6. hydraulic change-speed gear comprising a frame, a motor unit and a pump unit in said frame, each unit having a casing and a rotor, each casin having a cylindrical part, sald c lindrica part having a passage extending rom its inside to its outer face,

a motor unit and a pump unitv casing in said frame, and a connecting element between said casings, said element being fixed to one of said casings and adapted to movewithin limits with respect to the other 4 casing.

l 7. A hydraulic change-speed gear compris ing a frame, a motor unit and a pump unit in said frame, each unit having a casing and a rotor arranged eccentrically in its casing, a connecting element between said casings which is secured to one casing and adapted to move within limits with respect to the other casing,`and means for varylng the position -of the last-mentioned casing with respect to its rotor independently of the other casing.

8. A hydraulic change-speed gear comprising a frame, a motor unit and a pump `unitin said frame, each unit having a casing adapted to be displaced in said trame so asv to vary its position with respect to its rotor, a .connecting element between said casings l which is secured to one casing and adapted facs to move within limits with respect to the other casing, and means attached to one of said casings for displacing it in said frame.-

9; A hydraulic change-speedgear comprising a frame, a motor unitand a pump unit in said frame, each unit having a casing adapted to be displaced in said frame so as to vary its position with respect to its rotor, means attached to one of said casings Jfor displacing casings, a dog on said rod, and an abutment on vthe other casing adapted to engage said do on said rod in a given relative position o said rod and said'casing r 10. A hydraulic change-speed gear comprising a frame, a motor unit and a pump it in said frame, a rod secured to one' of said unit in said frame,` each unit having a cas-I ing and a rotor arranged eccentrically in its casing, a connecting element between .aid casings which 'is secured to one casing and ada ted to move within limits with respect to t e other casing, means for varying the position of the last-mentioned casing with'l respect to its rotor independently of the other casing, and pipes connecting said casings and adapted to maintain their connection notwithstanding the relative displacement of said casings.

4llfA hydraulicv chan e-speed gear colllprising a motor unit an a pump unit, each -u'nit havingl a casing and a rotor, means for reversing t c unit, means for varying the relative positlon of said casin and said rotor of each unit,

and aconnecting element'between those parts of the units which are displaced Vfor varying said relative position, said element being ixed to one of said parts and adapted t0 move within limits with respect to the other part.Y p

In testimony whereof I aix my signature. WILHELM AKHN;

e -iiow of liquid from said pump 

